Method and system for delivering cardiac resynchronization therapy with variable atrio-ventricular delay

Abstract

A pacing system computes optimal cardiac resynchronization pacing parameters using intrinsic conduction intervals. In various embodiments, values for atrio-ventricular delay intervals are each computed as a function of an intrinsic atrio-ventricular interval and a parameter reflective of an interventricular conduction delay. Examples of the parameter reflective of the interventricular conduction delay include QRS width and interval between right and left ventricular senses.

What is claimed is: 
     
       1. A cardiac rhythm management system, comprising:
 a plurality of sense amplifiers configured to sense cardiac electrical activity; 
 a plurality of pulse generators configured to deliver pacing pulses; and 
 a controller for controlling delivery of the pacing pulses, the controller programmed to:
 control delivery of ventricular pacing pulses of the pacing pulses using a programmable atrio-ventricular delay (AVD) interval in accordance with an atrial tracking or atrio-ventricular (AV) sequential pacing mode; 
 determine a present atrial rate; 
 determine whether an optimum value of the AVD interval associated with the present atrial rate exists in a table; and 
 set the AVD interval to the optimum value if the optimum value exists in the table. 
 
 
     
     
       2. The system of  claim 1 , wherein the controller is further programmed to interpolate between two optimum AVD values in the table if the optimum value does not exist in the table, the two optimum AVD values being optimum values of the AVD interval associated atrial rates above and below the present atrial rate. 
     
     
       3. The system of  claim 1 , wherein the controller is further programmed to compute the optimum value if the optimum value does not exist in the table; and
 initialize or update the table using the computed optimum value. 
 
     
     
       4. The system of  claim 3 , wherein the controller is programmed to measure an intrinsic conduction parameter; and
 compute the optimal value as a linear function of the measured intrinsic conduction parameter. 
 
     
     
       5. The system of  claim 4 , wherein the controller is programmed to measure an interval between a right atrial sense or pace and a left atrial sense as the intrinsic conduction parameter. 
     
     
       6. The system of  claim 4 , wherein the controller is programmed to measure an intrinsic AV interval between an atrial sense or pace and a ventricular sense as the intrinsic conduction parameter. 
     
     
       7. The system of  claim 6 , wherein the controller is programmed to measure a parameter reflective of an interventricular conduction delay, and the controller is programmed to compute an optimal value for the AVD interval as a linear function of the measured intrinsic AV interval and the parameter reflective of the interventricular conduction delay. 
     
     
       8. The system of  claim 7 , wherein the controller is programmed to measure an interval between right and left ventricular senses as the parameter reflective of an interventricular conduction delay. 
     
     
       9. The system of  claim 1 , comprising an implantable device including the plurality of sense amplifiers, the plurality of pulse generators, and the controller. 
     
     
       10. The system of  claim 9 , wherein the implantable device is configured to deliver a cardiac resynchronization therapy. 
     
     
       11. A method for operating an implantable cardiac rhythm management device, comprising:
 sensing cardiac electrical activity using the implantable cardiac rhythm management device; 
 delivering pacing pulses from the implantable cardiac rhythm management device; 
 controlling delivery of ventricular pacing pulses of the pacing pulses using a programmable atrio-ventricular delay (AVD) interval in accordance with an atrial tracking or atrio-ventricular (AV) sequential pacing mode; 
 determining a present atrial rate; 
 determining whether an optimum value of the AVD interval associated with the present atrial rate exists in a table; and 
 setting the AVD interval to the optimum value if the optimum value exists in the table. 
 
     
     
       12. The method of  claim 11 , further comprising interpolating between two optimum AVD values in the table if the optimum value does not exist in the table, the two optimum AVD values being optimum values of the AVD interval associated atrial rates above and below the present atrial rate. 
     
     
       13. The method of  claim 11 , further comprising:
 computing the optimum value if the optimum value does not exist in the table; and 
 initialize or update the table using the computed optimum value. 
 
     
     
       14. The method of  claim 13 , wherein computing the optimum value comprises:
 measuring an intrinsic conduction parameter; and 
 computing the optimal value as a linear function of the measured intrinsic conduction parameter. 
 
     
     
       15. The method of  claim 14 , wherein measuring the intrinsic conduction parameter comprises measuring a first interval between a right atrial sense or pace and a left atrial sense. 
     
     
       16. The method of  claim 14 , wherein measuring the intrinsic conduction parameter comprises measuring a first interval between an atrial sense or pace and a ventricular sense. 
     
     
       17. The method of  claim 16 , wherein measuring the at least one intrinsic conduction parameter comprises measuring a second interval between right and left ventricular senses, and computing the optimal value for the AVD interval comprises computing an optimal value for the AVD interval as a linear function of the measured first and second intervals. 
     
     
       18. The method of  claim 11 , comprising deriving coefficients for the linear function from a linear regression analysis of clinical population data relating different values of the intrinsic conduction parameter to an optimum AVD interval for delivering cardiac resynchronization therapy as determined by measurement of a cardiac function parameter. 
     
     
       19. The method of  claim 18 , comprising indicating the optimum AVD interval for delivering cardiac resynchronization therapy by a maximum value of the cardiac function parameter. 
     
     
       20. The method of  claim 19 , comprising measuring a left ventricular pressure change, an arterial pulse pressure, or a cardiac output as the cardiac function parameter.